Method of heating material



`sept.12,1933. wfs. KING Erm. ,1 1,926,544

METHOD 0F HEATING MATERIAL Filed March 21, 1951 @M155 E', l 4%., K' 0% g Patented sept. .12, 1933 ineen .regata l rirrnoirouanirrrne Marsman Welty S. King, Youngstown, Joseph il. Barliak,

Campbell, and Charles E. lllarris,a Youngs-1,

town, @hic Application March 2l, i931. Serial NV `524,278

bl Claims.

rI'his invention relates to the heating ci metal sheets, bars, plates, and the like, generally preparatory to subsequent operations such as rolling, forging or forming, as Well as to the heat treatment of metals for attainment of optimum physical properties.

For eiilcient perfomance of such heating operations, the material should be raised to the desired temperature in a minimum of time with the expenditure of a minimum of fuel and Without extensive oxidation and scaling of the rnetal. To this end, it is desirable to employ a luminous flame since because oi its radiant character the f rate ci' heat transfer therefrom is higher than from a non-luminous flame of like temperature. A body may therefore be heated to a given ternperature in a given time either by a luminous :dame of relatively low temperature or by a nonlurninous one oi relatively high temperature, or may be heated to a given degree by aluminous llame in a shorter time than by a non-luminous one of the same temperature.

1t is further Vknown it is desirable to eiiect the heating in a reducing atmosphere so as to reduce scaling and oxidation of the metal which generally results from the presence of an excess 'of oxygen in the burning gases and which, in the ordinary methods of combustion heretofore practiced, it is extremely dimcult to prevent. A common method of creating such a reducing at- Inosphere Within the furnace is to increase the proportion of gas to air supplied or 'to reduce the proportion of air to gas supplied, but this procedure is not only wasteful or fuel but does not result in the production of the desirable luminous or radiant flame without which, as heretofore explained, maximum eiliciency of heat Atransference cannot be eected.

A principal object of the present invention, therefore, is to provide a novel method of heating material in a gas fired furnace by means of which a'luminous heating flame is produced and a reducing atmosphere maintained within the furnace, the method contemplating' preliminary enrichment of` the fuel gas by suitable treatment With a hydrocarbon and resulting in, among other things, more eicient heating conditions than have heretofore been'generally obtainable, and a considerable saving in material, rst, through'substantial elimination of loss of the material itself by oxidation and scaling and, second, because less material is thereby rendered uniit for subsequent rolling and like operations.

A further obiect of the invention is to minimize the time required to heat the material to a given point. o

A still further object of the invention is the production on the articles heated of a thin protective coating adapted to prevent them from sticking together in subsequent operations as, for example, when sheets after the heating are piled together preparatory to subsequent rolling, thus avoiding the necessity for the usual charcoal dipping of alternate sheets or equivalent operations required when sheets are heated by the methods commonly invogue.

The invention further includes various otherobjects, novel features and operations hereinafter more particularly pointed out or Which will be apparent as the description of the invention proceeds.

To enable those skilled inthe art to comprehend and practice the invention, we shall now describe one manner of performing the method thereof, during which reference will be had to the accompanying drawing in which We have diagrammatically shown one form of apparatus particularly adapted for the purposes of the invention, and it Will be more convenient to rst explain the apparatus and then refer toits manner ofoperaticn in the practice of the method.

Referring to the drawing, therefore, the single diagrammatic figure of which may be considered as a substantial side elevation, the apparatus is shown therein' as applied to a furnace F which may be of any type suitable for the treatment of sheets, bars, plates, or other generally similar material. A

Fuel gas for combustion is initially supplied from any suitable source such as a gas producer P from which a main Vgas conduit 1 is extended toward the furnace and suitably connected to the burner or burners thereof either directly, or when the furnace is provided with a plurality of burners, to a header extending adjacent the burners to which the latter are individually connected. For,convenience We have assumed the furnace is equipped with two burners (not shown) and the conduit therefore providedwith branches 2, 3 respectively extending thereto.

Leading from the source of gas supply P is another conduit 4 which may be provided with a control valve 5 and which terminates within an operatively closed receptacle or casing 6 which for convenience We may term the carburetor. This carburetor is adapted to contain La suitable hydrocarbon, desirablytar, although under certain conditions benzol, oil or various other materials may be found satisfactory, and is provided with a port covered by a removable lid 1 through which the hydrocarbon may be introduced in quantity suilicient to partly fill the carburetor preferably about to the level indicated by the line 8. The conduit 4is extended down into the casing so as to terminate either slightly above the level of the hydrocarbon, as shown, or else somewhat below that level, and for the material in a fluid or substantially uid condition a steam coil 9 or other heating` medium may be arranged within the casing and supplied with steam through inlet and outlet lines 10, 11.

From the upper part of the carburetora conduit 12 is extended; as shown', thisconduit is provided with branches 13, 14 respectivelydirected to cleaners l5, 16 conveniently which are of simllar construction, and which may thus respectively comprise a closed casing within which is desirably disposed a steam coil or other heating medium 1'1. As a matter of convenience, the lsteam or other heating medium may, as shown, be'led from a supply pipe 18 upwardly through the coil 1'1 in the cleaner 16, thence through the inlet pipe 10 to the bottom of thecoil 9 in the carburetor, and thence through the outlet pipe 11 to the top of the coil 17 in the cleaner 15 and discharged from the latter through the outlet 19, a valve 20 suitably positioned in the pipe 18 being desirably provided to regulate the passage of the steam.

From a point adjacent the top of the casing of the cleaner 15 a conduit 21, which may include a control valve 22, is led to the branch 2 of the main conduit l, and in like manner another conduit 23, which may likewise include a control valve 24, is led from the upper part of the: casingof the cleaner 16 to the branch 3 of the main conduit. Desirably, each of the cleaner casings as well as the carburetor casing is provided near its bottom with a valve controlled outlet 25 through which the hydrocarbon material contained in the carburetor and the residues collecting in the cleaners may be drawn off when and as desired.

In the practice of the method of our invention by means of an apparatus of the general character of that to which we have referred, a portion of the gas which is to be burned in the furnace isdrawn from the producer P or other source through the conduit 4, while the remainder passes directly to the furnace through the conduit 1 and branches 2, 3.' The'l gas -passing through the conduit 4 enters the carburetor and is there either drawn over the tar or other hy- I 1 drocarbon contained therein in case the conduit terminates -above its level as shown, or through the hydrocarbon in case the level of the latter reaches above the lower endof the conduit; in either case, the resultant effect is to enrich the gas with hydrocarbon to a point materially in excess of its normal hydrocarbon content as it issues from the producer or other source P. From' the carburetor the enriched gas passes upwardly through Y the conduit 12 and thence through the conduits 13, 14 respectively to the cleaners 15, 16, in each of which its velocity is diminished so that a considerable portion of the entrained particles and other impurities are re- -leased and fall to the bottom of the cleaners,

from which they may be drawn of! from time to Atime through -the outlets 25. The cleaned but enriched gas then passes through the conduits 21 and-23 to the branches 2, 3 of the main conduit, where it mixes with the unenriched gas coming directly from the producer preparatory to combuston in the furnace, with resulting production 'riching treatment by passing all of it through of a luminous ame and a reducing atmosphere therein.'

VWhile the form of apparatus to which we have referred is a convenient one, it is of course capable of modification in many particulars to adapt it for use with diierent numbers of burners and/or under variant conditions encountered in commercial installations. In many cases, the use of but one cleaner may be found desirable, and it will be apparent that the conduit leading therefrom may then be tapped directly into the main conduit l or into the header with which it is usually connected when a considerable number of burners are employed. the ultimate object in any case being to providesuicientV hydrocarbon enrichment of the fuel gas when` delivered to the burner or burners to produce a luminous flame and reducing atmosphere within the furnace when it is burned therein. To this end it will generally be preferred to treat onlyA a portion of the total fuel gas with the hydrocarbon asherein more particularly described, but it is within the contemplation and purview of our invention to subject all of the fuel gas to such enthe carburetor preparatory to deliveryy to the furl nace, the apparatus in such case being of course suitably modified to effect this result.

` It will be understood that the provision of heating means in the carburetor, and preferably in the cleaners as well, is' for the purpose of maintaining their contents in fluid `or substantially uid condition, a greater or less amount of heat being utilized in accordance with the particular conditions surrounding the installation and the nature of the hydrocarbon employed.

While for convenience of illustration we have shown in the drawing the conduit 21 as considerably longer than the conduit 23,.it will usually be found preferable when two or more cleaners are employed to make the delivery conduits therefrom of substantially equal length so that the draft therethrough will be similar and also to arrange the other conduits in such manner as likewise to equalize their draft to the end that.

' as will be readily understood by those familiar material being heated, thus enabling a given heat transference to be effected thereto in a' given time by the' use of a Vflame of lower temperature than has heretofore been practicalv in` heating operations of the character of those to which our invention relates, while the maintenance of a4 reducing atmosphere within the furnace and absence of excess oxygen minimize oxidation of the material and production of scale thereon.

Moreover, it is found that a thin protective coating is produced on material heated in accordance with our method which is effective to prevent the sticking together of pieces of the materialwhen they are later piled on each other. This is of especial advantage in the case of sheets which, after the heating, lare customarily piled eration which consumes considerable time and is relatively costly. Sheets heated in accordance m with our method. however, and. thus provided Lemme .5 the cost of production correspondingly lowered.

It will be epperent from the foregoing thet our improved method. of heating meteriol is cepebie in practice of considereble' verietion without departing from the principles thereof es herein disclosed end further, that apparatus of forms other then that to which we heve referred may be einpioyed in its perfor-meme ii desired; end it is therefore our intention neither to conne nor restrict ourselves to any precise details of opere," tion in the practice of the method, norte any perticuior form oi epperetus for carrying it out so ione es they fell within the spirit end scope of the invention ee destined in tire appended claimsn I Herring ttiiie described our invention, We oioini one. desire to protect roy Letters Peteur, oi the States:

i. The nie-tiro@ oi" heetirig meteriei in e 3 fired furnace which comprises the steps of bring- 'ing iuei gee into contect with e hydrocerbonto enhance' the normal amount of hydrocarbons e contained in the gee, then mining the gas so exiriohed with hydrocarbon with the other fuel gee containing e. normal amount thereof, and naliy burning the mixture in the iurnece in sucia menner as to produce therein e, luminous vneme eine e. reducing etmospiiere.

3. The method civ heeting materiel in e. este` Eredi furnece which comprises the steps of iiicreeeing the nornool iiydrocorbon content ot port @nelly burning the mixture in the i'iirnece in auch.

roe-nner es toprociece e rement Home one reducn one etmospnere therein stirring the meeting of the meteriei,

Tire method oi neetine inet-ei eirieete end the iii-ie in e, eee fomece with resultant pro-z duction ci e tiiin protective coeting noem-.ed to prevent erinerence et eriecerit sheets when scese oiientiy wie@ enti compressi-ee together, which comprieee time etenI ci' meeting time sheets in e reducing etnioepnere by moons oi e, 'eeeeous neme derived from combustion oi incl eee enriched with hydroeeirieone crier to combustion to e suin iicient extent to render it luminous.

WELTY S. KING.

JSWH P; BARMAK. @mg E. i-ZARRE vmel 

